1. Field of the Invention
The present invention relates to a process for the manufacture of suture needles and, more particularly, relates to a process for enhancing the physical strength of the suture needles through an expedient and novel cold-working or cold-forming procedure. Moreover, the invention also relates to the provision of a novel and physically strengthened suture needle, particularly a surgical suture needle possessing a curvilinear configuration wherein the cross-sectional configuration of the needle is cold-formed into varying shapes in order to produce a needle having superior physical characteristics and strengths imparted thereto through the inventive process.
2. Discussion of the Prior Art
Currently, various types of processes are known and widely utilized in the technology relating to the manufacturing of suture needles, and particularly needles which are adapted to have sutures fastened thereto by means of various types of procedures so as to meet the stringent requirements of the suture needle-manufacturing technology for so-called armed sutures. Generally, suture needles are formed from suitable metals, especially such as different types of stainless steel, wherein the needles are produced from thin rod material which is ordinarily cut into appropriate lengths commensurate with the length of the intended suture needle. The severed length of rod usually has one end thereof formed into a needle point, or has a needle point attached to that end, and has appropriate cross-sectional dimensions imparted thereto, such as through stamping, laser processing, grinding or the like, and thereafter curved into the finished curvilinear configuration prior to the attaching thereto of a suture. Sutures are then attached to the end of the formed suture needle opposite the needle point through either the application of suitable adhesives, or by being placed into a groove formed at that end of the needle and thereafter the suture-needle assembly swaged to formulate an appropriate permanent fastening between the needle end and the contiguous end of the suture, thereby forming a so-called armed suture arrangement.
In some instances, the metallic material of the suture needle is also subjected to a heat treatment in order to complete the needle manufacturing process.
Among various processes directed to the forming of suture needles are those disclosed in Kawada et al. U.S. Pat. No. 4,672,734. In that instance, various shapes are imparted to the suture needle prior to the curving thereof into its final configuration. Such shapes may include the stamping into the needle surface of various cross-sectional configurations along the length of the needle which is to be formed; for example, including the forming of grooves or rolling of the material into a tubular shape to enable the insertion therein of suture ends for subsequent attachment to the needle. Thereupon, the cross-sectionally shaped needle is subjected to bending in order to impart the desired curvature thereto and to provide the needle with its finished configuration.
The above-mentioned U.S. patent, although providing an improvement over the existing state-of-the-art in the manufacture of suture needles, still does not produce a suture needle construction possessing an enhanced physical strength in comparison with the previous state-of-the-technology, in that it essentially requires the needle to be curved subsequent to imparting the various cross-sectional shapes thereto, which quite often, causes the inherently resilient nature of the metal employed for the suture needle, such as high-quality stainless steel to cause the needle to resiliently "spring back" to some degree or in effect, to "uncurve". This will at times produce a needle construction and curvature which is not in strict conformance with the intended final dimensions and curvature of the surgical needle, while concurrently rendering the process relatively expensive and cumbersome. This imposes serious problems on being able to implement a satisfactory quality control over the suture needles, leading to numerous rejects and rendering the manufacturing process not only laborious and cumbersome but frequently highly uneconomical.